Astrophysicist Neil DeGrasse Tyson. Death by Black Hole

[humanino]

I will try to summarize and forget about this thread.

Forget this thread all you want, I don't want other people to visit PF and read wrong scientific facts on it.

any object occupies the same amount of space relative to itself

Locally yes, you are right. But your body does not occupy a single point in space. Just think that the gravitational field becomes so intense, that your feet accelerate differently from your head ! That should be scary enough. Eventually, according to classical relativity, even atoms and nucleons are torn apart.

Voila.

Voila rien, c'est d'la merde.

 

[Ivan Seeking]

I'm sure you are not young enough to have forgotten. It is 42.

Darn! I was thinking of 43. Oh well.

Since you have shown that there is at least one Graviton, you will have to come over if you want your beer.

 

[humanino]

Since you have shown that there is at least one Graviton, you will have to come over if you want your beer.

Or organize the next PF gathering at my place

Thank you for the invitation ! Since I always want beer, does it mean that, unless I organize this PF gathering in a reasonable amount of time, I must come or I will contradict myself ?

 

[Crazy Tosser]

Forget this thread all you want, I don't want other people to visit PF and read wrong scientific facts on it.
Locally yes, you are right. But your body does not occupy a single point in space. Just think that the gravitational field becomes so intense, that your feet accelerate differently from your head ! That should be scary enough. Eventually, according to classical relativity, even atoms and nucleons are torn apart.
Voila rien, c'est d'la merde.

It's ok. Famous "astrophysicists" talking about things they do not know or understand on TV is much scarier.

The concern I was addressing is not the tidal forces, but once again (sigh) statements he made between [4:10] and [4:40] - that an object "occupies a different amount of space" and that causes it to be "squeezed through the "fabric" (ain't quotes big enough or red enough) of space". If you agree with that statement, it's your problem, General Relativity doesn't.

 

[Stingray]

I don't see anything wrong with talking about being "squeezed through the fabric of spacetime." It's colorful language, but he wasn't giving a technical talk. Even if he was, there really isn't anything wrong with it. There's no contradiction with GR.

The bit about occupying different amounts of space makes a lot less sense, so I would perhaps agree with that criticism. Your attempted corrections don't really improve the situation, however.

 

[humanino]

The concern I was addressing is [...] that an object "occupies a different amount of space" and that causes it to be "squeezed"

Let us consider other crackpot references.
What happens to you if you fall into a black hole?

John Baez[/URL]]I have to hit the singularity eventually, and before I get there there will be enormous tidal forces-- forces due to the curvature of spacetime-- which will squash me and my spaceship in some directions and stretch them in another until I look like a piece of spaghetti.

§32.6. THE FATE OF A MAN WHO FALLS INTO THE SINGULARITY AT R = 0

Consider the plight of an experimental astrophysicist who stands on the surface of a freely falling star as it collapses to R = 0.
As the collapse proceeds toward R = 0, the various parts of the astrophysicist's body experience different gravitational forces. His feet, which are on the surface of the star, are attracted toward the star's center by an infinitely mounting gravitational force; while his head, which is farther away, is accelerated downward by a somewhat smaller, though ever rising force. The difference between the two accelerations (tidal force) mounts higher and higher as the collapse proceeds, finally becoming infinite as R reaches zero. The astrophysicist's body, which cannot withstand such extreme forces, suffers unlimited stretching between head and foot as R drops to zero.
But this is not all. Simultaneous with this head-to-foot stretching, the astrophysicist is pulled by the gravitational field into regions of spacetime with ever-decreasing circumferential area, 4\pi r^{-2}. In order to accomplish this, tidal gravitational forces must compress the astrophysicist on all sides as they stretch him from head to foot. The circumferential compression is actually more extreme than the longitudinal stretching; so the astrophysicist, in the limit R\rightarrow0, is crushed to zero volume and indefinitely extended length.

Remember that, at least as soon as nuclei, an absolute scale is defined by the size of hadrons (so-called \Lambda_\text{QCD}).

 

[Ivan Seeking]

Or organize the next PF gathering at my place

Thank you for the invitation ! Since I always want beer, does it mean that, unless I organize this PF gathering in a reasonable amount of time, I must come or I will contradict myself ?

Just keep a beer in your hand and no paradoxes will be apparent.

That gives me an idea: Black Hole Beer - the beer that no one can resist.

 

[hypatia]

humanino...

 

[Chi Meson]

Let us consider other crackpot references.

McIrvin? Thorne? Wheeler? They have ALL been on TV! For that matter, so has Feynman! How can you trust anything they say?

 

[Ivan Seeking]

McIrvin? Thorne? Wheeler? They have ALL been on TV! For that matter, so has Feynman! How can you trust anything they say?

Indeed! I often find it amusing that somehow a expert on TV is seen as being less qualified than an expert who writes a book.

Conversely, there are many times that my parents will get all excited about something seen on TV when I've told them the same thing before. Then they call me to tell me all about it.

 

[Quantum_Grid]

Man, I was skimming over threads and all I saw was "Neil Degrasse Tyson: Death by..."

I thought, oh man, no way he died! lol

 

[glueball8]

Wow, Newton invented integral calculus in 3 month? :O I can't even learn basic calculus in 3 month. Oh man I feel dumb. :\